膨胀剂和后浇带对超长环形底板混凝土防裂的影响研究  

Research on the Influence of Expansion Agent and Post Pouring Strip on the Cracking Prevention of Super Long Annular Base Plate Concrete

作　　者：任锦龙 荣慕宁 王振红[2] 邢国荣[1] 汪娟 张步 张凯恒 REN Jinlong;RONG Muning;WANG Zhenhong;XING Guorong;WANG Juan;ZHANG Bu;ZHANG Kaiheng(Beijing Construction Engineering Group Co.,Ltd.,Beijing 100055,China;Structural Material Institute,China Institute of Water Resources and Hydropower Research,Beijing 100038,China)

机构地区：[1]北京建工集团有限责任公司,北京100055 [2]中国水利水电科学研究院结构材料所,北京100038

出　　处：《水力发电》2024年第6期61-66,共6页Water Power

基　　金：国家重点研发计划项目(2021YFC3090102,2021YF-C3090104);国家自然科学基金资助项目(52192672);流域水循环模拟与调控国家重点实验室自主研究项目(SKL2022ZD05)。

摘　　要：世界上亮度最高的第四代高能同步辐射光源的超长环形底板周长约1494 m、厚1 m,如何保证底板混凝土施工质量防止裂缝产生是工程的难点。建立有限元三维数值分析模型,按照实际施工过程仿真底板混凝土的跳仓浇筑过程,模拟分析底板混凝土温度及温度应力变化情况,同时将计算温度结果与实测温度结果进行对比,验证热学参数的合理性和准确性。在反演分析基础上,研究膨胀剂和后浇带的温控防裂效果。研究结果表明:早膨胀型自变(Ⅰ型)对混凝土早龄期应力的影响是有利的,但晚膨胀型自变(Ⅲ型)的延迟膨胀性补偿由于混凝土收缩和温降引起的应力,有利于减小底板冬季最大拉应力;设置后浇带能减小底板混凝土分缝分块长度,削减混凝土最大拉应力,削减幅度为6.65%。The fourth generation high-energy synchrotron radiation light source with the highest brightness in the world has an ultra long annular base plate with a circumference of approximately 1494 m and a thickness of 1 m.How to ensure the construction quality of concrete floor and prevent cracking is a difficult problem in the project.By using the finite element three-dimensional numerical analysis program,the jumping pouring process of base plate concrete is simulated according to the actual construction process,and the temperature and temperature stress changes of the base plate are also simulated and analyzed.The calculated temperature results are compared with the measured temperature results to verify the rationality and accuracy of thermal parameters.On the basis of inverse analysis,the temperature control and cracking prevention effects of expansion agents and post pouring strips are studied.The research results indicate that,(a)early expansion type autogenous deformation(Type I)has a favorable effect on the early age stress of concrete,but the delayed expansion compensation of late expansion type autogenous deformation(Type III)is beneficial for reducing the maximum tensile stress of the base plate in winter due to the stress caused by concrete shrinkage and temperature drop;and(b)as setting up a post pouring strip can reduce the length of base plate concrete pouring blocks,the maximum tensile stress of the concrete can be reduced by 6.65%.

关 键 词：混凝土 环形底板 膨胀剂 后浇带 反演分析 温度应力 

分 类 号：TV315[水利工程—水工结构工程]